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Cost-effectiveness of a new system in ruling out negative urine cultures on the day of administration

Abstract

Urine samples account for a significant part of the workload in clinical microbiology laboratories. However, the culture process is time-consuming and a large proportion is reported as negative. To reduce unnecessary culture procedures and speed up the reporting of negative results, a reliable screening method is needed. For this purpose, urine samples submitted to our clinical microbiology laboratory were simultaneously screened by a flow cytometry method (Sysmex UF-1000i, Japan). During screening, the evaluation of various combinations of leucocytes and bacteria cut-offs demonstrated that cut-offs of 30 and 50/μL, respectively, were the best threshold values to reach a 100% negative predictive value (NPV) with a culture reduction rate of 44.8% in adults and 61.9% in children between the ages of 6 and 17 years. With the culture reduction rates mentioned above, the screening method has provided at least 24% savings in expenditures of the routine clinical microbiology laboratory. Since we did not reach such an NPV with any combinations of screening parameters in children younger than 5 years of age, we recommend cultivation of all urine samples in those patients without a screening step. In conclusion, Sysmex UF-1000i as a screening method was capable of improving the efficiency of the routine microbiology laboratory by providing negative results in a few minutes in children greater than 6 years of age and in adults.

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Correspondence to A. Ilki.

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This study was partly supported by an in-kind grant from Sysmex Corp., Turkey.

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The authors declare no conflict of interest.

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This article does not contain any studies with any human participants or animals performed by any of the authors.

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This study did not involve human subjects or samples; therefore, no informed consent is required.

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Ilki, A., Ayas, R., Ozsoy, S. et al. Cost-effectiveness of a new system in ruling out negative urine cultures on the day of administration. Eur J Clin Microbiol Infect Dis 36, 1119–1123 (2017). https://doi.org/10.1007/s10096-017-2898-7

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Keywords

  • Urine Sample
  • Negative Predictive Value
  • Microbiology Laboratory
  • Receiver Operating Curve
  • Clinical Microbiology Laboratory